Phoebe Star, from St. Vincent’s Centre for Applied Medical Research in Sydney, and colleagues describe the case of a 44-year-old male patient presenting with blackened skin overlying veins. The patient had systemic sclerosis and had commenced minocycline for rosacea treatment five months earlier.

The researchers identified hemosiderin deposition in the dermis and pigmented macrophages within the subendothelial layer of the vein wall on histological examination of the discolored tissue and underlying vein; the staining pattern was consistent with minocycline-induced pigmentation. The patient chose to continue taking minocycline to control his rosacea. In follow-up ultrasound the treated vessels were fully occluded with no evidence of recanalization, residual flow, or ongoing thrombophlebitis. The pigmentation did not subside over two years, despite good sclerotherapy outcome.